vulkan: track the right value on CmdSetColorWriteMasks

Fixes: 092be5a329 ("vulkan: Add more dynamic color blend states")

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21509>

src/vulkan/runtime/vk_graphics_state.c

@@ -2542,7 +2542,7 @@ vk_common_CmdSetColorWriteMaskEXT(VkCommandBuffer commandBuffer,
       uint32_t a = firstAttachment + i;
       assert(a < ARRAY_SIZE(dyn->cb.attachments));
 
-      SET_DYN_VALUE(dyn, CB_BLEND_EQUATIONS,
+      SET_DYN_VALUE(dyn, CB_WRITE_MASKS,
                     cb.attachments[a].write_mask, pColorWriteMasks[i]);
    }
 }